Estimation de l'Incidence de l'Infection par le VIH et autres Indicateurs de Surveillance de l'Épidémie du VIH : le cas de la France et du Cameroun

A possible solution to eliminate the spread of the HIV epidemic is that people living with HIV (PLHIV) unaware of their HIV status (the hidden epidemic) are diagnosed and that all PLHIV have timely access to antiretroviral treatment (ART). That is why it is now recommended to put in place interventions combining early diagnosis of HIV and early initiation of ART. The objective of this thesis is to develop statistical methods to estimate indicators to identify, monitor and evaluate these interventions in different epidemic settings. Thus, a first back-calculation model combining HIV diagnosis data and changes in access to HIV screening is developed - with an application in France -to estimate the incidence of HIV infection, the duration between infection and HIV diagnosis and the size of the hidden epidemic. A multilevel analysis is implemented to identify risk factors associated with late ART initiation in Cameroon. A method based on multilevel models is proposed - with an application to Cameroon - to estimate two new indicators, the time between seroconversion and ART initiation and the delay between the theoretical time of ART eligibility and the effective time of ART initiation. A second back-calculation model more adapted to Africa countries is developed from data on PLHIV initiating ART - with an application in Cameroon - to estimate the incidence of HIV infection. This thesis proposes original methods to estimate the incidence of HIV infection and the time to HIV diagnosis or ART initiation.Une solution envisageable pour éliminer la propagation de l'épidémie du VIH est que les personnes vivant avec le VIH (PVVIH) ignorant leur statut sérologique (épidémie cachée) soient diagnostiquées et que les PVVIH aient accès rapidement au traitement antirétroviral (TARV). C'est pour cette raison qu'il est recommandé de mettre en place les interventions combinant notamment le dépistage précoce du VIH et l'initiation précoce du TARV. L'objectif de cette thèse est de développer des méthodes statistiques pour estimer les indicateurs permettant de désigner, de suivre et d'évaluer ces interventions dans différents contextes épidémiques. Ainsi, un premier modèle de rétrocalcul combinant les données de diagnostic du VIH et les changements dans l'accès au dépistage est développé, avec une application en France, pour estimer l'incidence de l'infection à VIH, la durée entre l'infection et le diagnostic du VIH et la taille de l'épidémie cachée. Une analyse multiniveaux est mise en œuvre pour identifier les facteurs de risque d'accès tardif au TARV au Cameroun. Une méthode basée sur les modèles multiniveaux est proposée, avec une application au Cameroun, pour estimer deux nouveaux indicateurs, la durée entre la seroconversion et l'initiation du TARV et la durée entre l'éligibilité théorique au TARV et son initiation effective. Un second modèle de rétrocalcul plus adapté aux pays d'Afrique est développé à partir des données des PVVIH mises au TARV, avec une application au Cameroun, pour estimer l'incidence de l'infection à VIH. Cette thèse propose des méthodes originales pour estimer l'incidence du VIH et le délai entre l'infection et le diagnostic du VIH ou l'initiation du TARV

Revealing geographical and population heterogeneity in HIV incidence, undiagnosed hiv prevalence and time to diagnosis to improve prevention and care : Estimates for France

Funding Information: LM, DC and VS thank INSEE and Réeseau Quetelet for kindly providing national and subnational statistics on population size (Donnéees harmoniséees des recensements de la population: Tabulation sur mesure, INSEE [producteur], ADISP-CMH [diffuseur]). LM, DC and VS also thank Christophe Godéereaux for optimizing the code written in C and Eric Janssen (OFDT) for sharing his estimates on drug use in France before publication as well as providing additional estimates. This work was supported by ANRS throughout the project ANRS 95017 INDIC and the framework of HIVERA JTC 2014. The sponsor had no role in the study. Publisher Copyright: © 2018 The Authors.To close gaps in HIV prevention and care, knowledge about locations and populations most affected by HIV is essential. Here, we provide subnational and sub-population estimates of three key HIV epidemiological indicators, which have been unavailable for most settings. Methods: We used surveillance data on newly diagnosed HIV cases from 2004 to 2014 and back-calculation modelling to estimate in France, at national and subnational levels, by exposure group and country of birth: the numbers of new HIV infections, the times to diagnosis, the numbers of undiagnosed HIV infections. The denominators used for rate calculations at national and subnational levels were based on population size (aged 18 to 64) estimates produced by the French National Institute of Statistics and Economic Studies and the latest national surveys on sexual behaviour and drug use. Results: We estimated that, in 2014, national HIV incidence was 0.17& (95% confidence intervals (CI): 0.16 to 0.18) or 6607 (95% CI: 6057 to 7196) adults, undiagnosed HIV prevalence was 0.64& (95% CI: 0.57 to 0.70) or 24,197 (95% CI: 22,296 to 25,944) adults and median time to diagnosis over the 2011 to 2014 period was 3.3 years (interquartile range: 1.2 to 5.7). Three mainland regions, including the Paris region, out of the 27 French regions accounted for 56% of the total number of new and undiagnosed infections. Incidence and undiagnosed prevalence rates were 2-to 10-fold higher than the national rates in three overseas regions and in the Paris region (p-values < 0.001). Rates of incidence and undiagnosed prevalence were higher than the national rates for the following populations (p-values < 0.001): born-abroad men who have sex with men (MSM) (respectively, 108-and 78-fold), French-born MSM (62-and 44-fold), born-abroad persons who inject drugs (14-and 18-fold), sub-Saharan African-born heterosexuals (women 15-and 15-fold, men 11-and 13-fold). Importantly, affected populations varied from one region to another, and in regions apparently less impacted by HIV, some populations could be as impacted as those living in most impacted regions. Conclusions: In France, some regions and populations have been most impacted by HIV. Subnational and sub-population estimates of key indicators are not only essential to adapt, design implement and evaluate tailored HIV interventions in France, but also elsewhere where similar heterogeneity is likely to exist.publishersversionPeer reviewe

Increased HIV Incidence in Men Who Have Sex with Men Despite High Levels of ART-Induced Viral Suppression: Analysis of an Extensively Documented Epidemic

Background: There is interest in expanding ART to prevent HIV transmission, but in the group with the highest levels of ART use, men-who-have-sex-with-men (MSM), numbers of new infections diagnosed each year have not decreased as ART coverage has increased for reasons which remain unclear. Methods: We analysed data on the HIV-epidemic in MSM in the UK from a range of sources using an individual-based simulation model. Model runs using parameter sets found to result in good model fit were used to infer changes in HIV-incidence and risk behaviour. Results: HIV-incidence has increased (estimated mean incidence 0.30/100 person-years 1990–1997, 0.45/100 py 1998–2010), associated with a modest (26%) rise in condomless sex. We also explored counter-factual scenarios: had ART not been introduced, but the rise in condomless sex had still occurred, then incidence 2006–2010 was 68% higher; a policy of ART initiation in all diagnosed with HIV from 2001 resulted in 32% lower incidence; had levels of HIV testing been higher (68% tested/year instead of 25%) incidence was 25% lower; a combination of higher testing and ART at diagnosis resulted in 62% lower incidence; cessation of all condom use in 2000 resulted in a 424% increase in incidence. In 2010, we estimate that undiagnosed men, the majority in primary infection, accounted for 82% of new infections. Conclusion: A rise in HIV-incidence has occurred in MSM in the UK despite an only modest increase in levels of condomless sex and high coverage of ART. ART has almost certainly exerted a limiting effect on incidence. Much higher rates of HIV testing combined with initiation of ART at diagnosis would be likely to lead to substantial reductions in HIV incidence. Increased condom use should be promoted to avoid the erosion of the benefits of ART and to prevent other serious sexually transmitted infections

HIV in hiding: methods and data requirements for the estimation of the number of people living with undiagnosed HIV

Many people who are HIV positive are unaware of their infection status. Estimation of the number of people with undiagnosed HIV within a country or region is vital for understanding future need for treatment and for motivating testing programs. We review the available estimation approaches which are in current use. They can be broadly classified into those based on prevalence surveys and those based on reported HIV and AIDS cases. Estimation based on prevalence data requires data from regular prevalence surveys in different population groups together with estimates of the size of these groups. The recommended minimal case reporting data needed to estimate the number of patients with undiagnosed HIV are HIV diagnoses, including CD4 count at diagnosis and whether there has been an AIDS diagnosis in the 3 months before or after HIV diagnosis, and data on deaths in people with HIV. We would encourage all countries to implement several methods that will help develop our understanding of strengths and weaknesses of the various methods

Estimation of HIV incidence in two Brazilian municipalities, 2013

ABSTRACT OBJECTIVE To estimate HIV incidence in two Brazilian municipalities, Recife and Curitiba, in the year of 2013. METHODS The method for estimating incidence was based on primary information, resulting from the Lag-Avidity laboratory test for detection of recent HIV infections, applied in a sample of the cases diagnosed in the two cities in 2013. For the estimation of the HIV incidence for the total population of the cities, the recent infections detected in the research were annualized and weighted by the inverse of the probability of HIV testing in 2013 among the infected and not diagnosed cases. After estimating HIV incidence for the total population, the incidence rates were estimated by sex, age group, and exposure category. RESULTS In Recife, 902 individuals aged 13 years and older were diagnosed with HIV infection. From these, 528 were included in the study, and the estimated proportion of recent infections was 13.1%. In Curitiba, 1,013 people aged 13 years and older were diagnosed, 497 participated in the study, and the proportion of recent infections was 10.5%. In Recife, the estimated incidence rate was 53.1/100,000 inhabitants of 13 years and older, while in Curitiba, it was 41.1/100,000, with male-to-female ratio of 3.5 and 2.4, respectively. We observed high rates of HIV incidence among men who have sex with men, of 1.47% in Recife and 0.92% in Curitiba. CONCLUSIONS The results obtained in the two cities showed that the group of men who have sex with men are disproportionately subject to a greater risk of new infections, and indicate that strategies to control the spread of the epidemic in this population subgroup are essential and urgent

Predictors of poor retention on antiretroviral therapy as a major HIV drug resistance early warning indicator in Cameroon: results from a nationwide systematic random sampling

Retention on lifelong antiretroviral therapy (ART) is essential in sustaining treatment success while preventing HIV drug resistance (HIVDR), especially in resource-limited settings (RLS). In an era of rising numbers of patients on ART, mastering patients in care is becoming more strategic for programmatic interventions. Due to lapses and uncertainty with the current WHO sampling approach in Cameroon, we thus aimed to ascertain the national performance of, and determinants in, retention on ART at 12 months

Estimation of HIV incidence and others indicators of surveillance of the HIV epidemic : the case of France and Cameroon

Une solution envisageable pour éliminer la propagation de l'épidémie du VIH est que les personnes vivant avec le VIH (PVVIH) ignorant leur statut sérologique (épidémie cachée) soient diagnostiquées et que les PVVIH aient accès rapidement au traitement antirétroviral (TARV). C'est pour cette raison qu'il est recommandé de mettre en place les interventions combinant notamment le dépistage précoce du VIH et l'initiation précoce du TARV. L'objectif de cette thèse est de développer des méthodes statistiques pour estimer les indicateurs permettant de désigner, de suivre et d'évaluer ces interventions dans différents contextes épidémiques. Ainsi, un premier modèle de rétrocalcul combinant les données de diagnostic du VIH et les changements dans l'accès au dépistage est développé, avec une application en France, pour estimer l'incidence de l'infection à VIH, la durée entre l'infection et le diagnostic du VIH et la taille de l'épidémie cachée. Une analyse multiniveaux est mise en œuvre pour identifier les facteurs de risque d'accès tardif au TARV au Cameroun. Une méthode basée sur les modèles multiniveaux est proposée, avec une application au Cameroun, pour estimer deux nouveaux indicateurs, la durée entre la seroconversion et l'initiation du TARV et la durée entre l'éligibilité théorique au TARV et son initiation effective. Un second modèle de rétrocalcul plus adapté aux pays d'Afrique est développé à partir des données des PVVIH mises au TARV, avec une application au Cameroun, pour estimer l'incidence de l'infection à VIH. Cette thèse propose des méthodes originales pour estimer l'incidence du VIH et le délai entre l'infection et le diagnostic du VIH ou l'initiation du TARV.A possible solution to eliminate the spread of the HIV epidemic is that people living with HIV (PLHIV) unaware of their HIV status (the hidden epidemic) are diagnosed and that all PLHIV have timely access to antiretroviral treatment (ART). That is why it is now recommended to put in place interventions combining early diagnosis of HIV and early initiation of ART. The objective of this thesis is to develop statistical methods to estimate indicators to identify, monitor and evaluate these interventions in different epidemic settings. Thus, a first back-calculation model combining HIV diagnosis data and changes in access to HIV screening is developed - with an application in France -to estimate the incidence of HIV infection, the duration between infection and HIV diagnosis and the size of the hidden epidemic. A multilevel analysis is implemented to identify risk factors associated with late ART initiation in Cameroon. A method based on multilevel models is proposed - with an application to Cameroon - to estimate two new indicators, the time between seroconversion and ART initiation and the delay between the theoretical time of ART eligibility and the effective time of ART initiation. A second back-calculation model more adapted to Africa countries is developed from data on PLHIV initiating ART - with an application in Cameroon - to estimate the incidence of HIV infection. This thesis proposes original methods to estimate the incidence of HIV infection and the time to HIV diagnosis or ART initiation